I just cant wet or mess the diaper while sleeping

I have tried 3 table spoons of castor oil, drank caffeine before bed, took 2 sleeping pills and ate a lot before sleeping, but somehow, I don't feel the urgency to poop and my body wakes up when my bladder is full with pee. I think it is impossible for me.

I can't address messing your diaper as I've never entertained the thought. However, with regards to wetting your diaper, I suspect there's a psychological barrier. My suggestion is to teach yourself to pee in them while you're in bed. When you wake up (middle of the night or with the alarm in the morning) do not go to the bathroom to pee. Simply stay in bed, relax, and at some point you will feel you MUST pee. Then go ahead and pee. It will help if you drink an obscene amount of liquid before going to bed. If you feel the need to pee before falling asleep, do not go to the bathroom. Stay in bed. It may take a while; but, at some point you will be able to pee while laying in bed. Basically, you will be training yourself that it's okay to pee in bed. As time goes on, one night you'll likely wake up realizing you are in the middle of peeing. That's when the joy will be there for you.

If you really want to mess your diapers during the night and need help to do so, a strong laxative, taken at the appropriate time should get things going.

This is what I'd try if I really wanted a loaded diaper by morning.

Plan on having dinner with plenty of fiber, like peas and/or mashed potatoes about 4 - 5 hours before your usual bedtime. Near the beginning of the meal, take two Maximum Strength Ex-Lax pills and add a full adult dose of Miralax to your drink. After dinner move around a bit but don't aggressively exercise.

Near bedtime, drink another glass of water or a soothing tea again with a full dose of Miralax mixed in. BTW, Miralax is just about tasteless and undetectable in most drinks.

Go to bed and put on a diaper plus protective or incontinent pants and relax and go to sleep. The laxatives should start to work a couple of hours after you are in bed, but it could take until near dawn. You should not feel much cramping but the urge to poo may well awaken you. You will probably fill your diaper, but you may wake up in the process.

When my partner wants in on the diaper game, he will put in a 24fr Foley and let it empty in his diaper. If he wants to mess he will take a laxative and put in a hollow butt plug. I never let him do both at once because the catheter is an open road to the bacteria to create a uti

I haven't been able to do that yet either but if I don't get up and go it will happen

You need to figure out how to relax to let the pee out. When I first started peeing in diapers many years ago when I got the urge I would wear a diaper and walk to the toliet like normal and act like peeing in toliet either standing or sitting. I then gradually started a little more not by toliet or laying in bed face down. So try to act like a normal pee process it will come. For pooping it was a little harder. I at first would use a suppository to poop in my diaper which was amazing but need to be careful using a ton then changed my diet when I wanted to poop and ate and drank food to make me poop like prunes and stuff. Now I poop in my diaper like a baby so amazing I wish u luck it will come give it time.